Help with ADO (not .NET) code for querying MAPI folder

I can't get the following subroutine to work. It's meant to query a MAPI public folder and return the first record. Can anyone tell me where I'm going wrong? It returns the error message: "Run-time error ‘-2147217900 (80040e19)’:" when it tries to open the recordset at the end of the routine.

Also, can you please explain why the second version of 'strUrlFolder (commented out) doesn't work?

Thanks

(PS - the code includes a custom function called Quote that simply adds quotes around a string value.)